Electric writing instrument



Mar. 6, 1923. 1,447,730 c. R. Pos1 ELECTRIC WRITING INSTRUMENT FiledNov. 24, 1920 l l S BY W ATTORNEY 5@ Patented Mar. 6, 1923.

UNITED STATES PATENT OFFICE.

CHARLES R. POST, OF NEW ROCHELLE, NEW YORK.

ELECTRIC WRITING INSTRUMENT.

To all wiz-0m z't may concern:

Be it known that I, CHARLES R. Posr, a citizen of the United States, andresident of New Rochelle, in the State of New York, have inventedcert-ain new and useful Improvements in Electric lVriting Instruments,of which the following is a specification.

An object of my invention is to provide a writing instrument having astylus or writing point to be heated sufficiently to scorch or burnpaper or analogous material to be written upon to prevent changing oraltering such writing. My invention isparticularly adapted for writingupon checks and documents to prevent alteration of the writing withoutdetection of the change.

Another object of my invention is to protect the stylus when not in useto avoid danger from the heated stylus.

My invention comprises novel details of improvement that will be morefully hereinafter set forth, and then pointed out in the claims.

Reference is to be had to the accompanying drawings, forming parthereof. where- 1n- Figure 1 is a side view of a writing instrument emboding my invent-ion on an enlarged scale; Iyig. 2 is a section on line 2,2 in Fig. 1; Fig. 3 is an enlarged detail section; Fig. 4 is a crosssection on line 4 4 in Fig. 3; Fig. 5 is a fragmentary detail section;Fig. 6 is a detail of a conductor; Fig. 7 is a diagrammatic viewillustrating an electric circuit for the instrument.

Similar numerals of reference indicate corresponding parts in theseveral views.

The barrel or handle member of the instrument is indicated at l, whichmay be of tubular form of insulating material; such as rubber or fibre.At the writing end the barrel is provided with a tubular tip 2 ofnon-heat conducting insulating material, such as asbestos. A metal heatconductor core or rod 3, preferably of copper, is located Within bore 2of tip 2 and has a tapering or pencil-like writing end 3a, in the natureof a stylus, projecting from tip 2. A stop 4 on core 3 near its Writingend bears against the outer end of tip 2 and a stop 5 on core Y3 withinbore 2 bears against shoulder 2" at the end of bore 2 of tip 2, wherebycore 3 is retained on the tip. The stops 4,

5 are shown in the form of split rings received in recesses 6, 7respectively of core or rod 3, whereby the latter is detachably retainedon the tip, moved and replaced. The arrangement described permits core 3to be removed from tip 2 and replaced by merely removing and replacingstop 4. Core 3 is to be heated to scorch or burn the paper or materialto be writ-ten upon. I have shown a conductor 8 coiled around core 3within tip 2 and extending from insulated line wires 9 of a cable 10 inthe barrel. The conductor 8 is a resistance wire capable of producingrequired heat around core 3 to roperly heat the latter. The resistancecon uctor 8 at its ends may be twisted to the line wires 9 and coveredby a winding 11 of asbestos cord to insulate the conductor. I have showna layer of mica 12 around core 3, a winding of insulated conductor 8around said mica, a layer 13 of mica over said winding and a winding ol'insulated conductor 8 over mica. 13. The inner winding of conductor 8 iswound from the inner end of core 3 to the outer part and the outerwinding of conductor 8 is wound over said inner winding continuing fromthe outer to the inner part of core 3. The covering 11 and the mica 12,13 thoroughly protect the resistance conductor 8 from theshort-circuiting bet-Ween the windings of the latter. By using conductor8 of very small gauge wire the 1nstrument may receive current from theordinary electric service lines in buildings, Without requiring acurrent regulator or resistance in the circuit to reduce the current.Vhen a conductor 8 of larger gauge is used any suitable regulator orresistance may be in the line to reduce the current flowing to conductor8, such as shown in Fig. 7 where the cable 1() and resistance lamp 14are in series in the fixture attached to the service line 15. Instead oflamp 14 a suitable resistance coil may be included in the circuit ofcable 10 to reduce current in winding 8. The resistance referred toenables the same to be located at a. suitable distance from the writinginstrument so that the heat of the resistance will not interfere withthe user of the instrument. The bore 2a of tip 2 is charged withinsulating material 16 embedding conductors 9, preferably of asbestos,thereby serving to force the heat since stop 4 may be refrom thewindings of conductor 8 forwardly toward the stylus. Any suitable switchmay be employed to control the flow of current through the wiring of theinstrument.

To protect the stylus when not in use I have provided a sleeve 0r tube17 slidably mounted upon barrel 1, open at the outer end, adapted toextend over and protect stylus 3a (Figs. 1 and 2) and to be slid alongthe barrel to expose the stylus, Fig. 3. A spring 18 coiled aroundbarrel l within protector 17 serves to automatically project theprotecting sleeve 17 forwardly when t-he sleeve is released. Said springbears at one end against a stop 19 on the barrel and at the other endagainst a stop 2O projecting inwardly from sleeves 17 which stop may bepunched from the sleeve. The stop 19 may be a split ring received in anlannular recess or groove 21 in barrel 1. The protector 17 has one ormore inwardly project-l ing lugs 22 to engage stop 19 to limit themovement of the protector along the barrel, so that the protector, willenclose the stylus when not in use. The barrel 1 is shown provided withan exterior annular recess or groove 23 near tip 2 to receive theinwardly extending rib 24 near the outer end of sleeve 17. Said sleeveis slit or divided longitudinally at 25 so that the adjacent portionsmay be squeezed or pressed inwardly to engage rib 24 in recess 23, toretain the sleeve in retracted position. The sleeve 23 is shown providedwith perforations 26 to permit circulation of air and escape of heat.

When the instrument is to be used the sleeve 17 is retracted from overthe stylus or writing point 3a to expose the latter and may be retainedby pressing the rib 24 into groove 23 by the fingers of the user, andthe current is caused to flow through the windings 8. The core 3 will beheated and the stylusy 3a will receive .sufficient heat to scorch orburn the paper or other material to be written upon, the instrumentbeing used in the nature of a writing pencil. When sleeve 17 is releasedthe spring will project the sleeve forwardly to protect the stylus, sothat if the instrument is laid upon a desk or papers while the stylus ishot injury will not result. The lateral flange 27 at the outer end ofsleeve 17 may rest upon the desk or papers to raise the sleeve there-'from to protect the same from heat and permit circulation of air aroundthe sleeve for cooling it.

My invention is particularly useful for writing names and amounts uponbank checks, notes and other instruments, since the heated stylus willscorch or burn the writing in the paper and so change its characterwhere written upon as to prevent alteration of the writing withoutleaving evidences of the change, whereby to render useless the raisingof checks and the like.

The barrel 1 may have one or more holes 1a for ventilation.

Having now described my inventioi1.\\'liat I claim is:

1. A writing instrument comprising a barrel provided at one end with anon-heat conducting tip, said tip having a bore conimunicating at itsinner end with the barrel, a heating core within said bore having astylus extending from the tip, a resistance conductor coiled around thecore within said bore, and conductors connected to said resistanceconductor and extending through said barrel from its outer end.

2., A writing instrument having a: tip provided with a bore having anopen inner end and a closed outer end, a core in said bore, a stylusextending from the core `through the closed end of the tip, a resistanceconductor coiled around the core wit-hin said bore, and meanscommunicating with said conductor through the inner end of said bore toconnect said conductor with a source of electric current.

3. A. writing instrument having a tip provided with a bore, a core insaid bore, a stylus extending from the core throughthe tip, a resistanceconductor coiled around the core within said bore, and means to connectsaid conductor with a source of electric eurrent, and a protectoradapted to enclose and expose said stylus.

4. An electric writing instrument com prising a barrel provided with astylus. means to heat the stylus, and a protector adapted to enclose andexpose the stylus.

5'. An electric writing instrument com pris ing a barrel provided with astjf'lus, means to heat the stylus, a protector sleeve slidable on thebarrel to enclose and expose the stylus, and a spring between the barreland protector and co-operative therewith to push the protector over thestylus.

6. An electric writing instrument comprising a barrel provided with astylus, means to heat the stylus, and a protector adapted to enclose andexpose the stylus. and means co-operative between the barrel andprotector to retain the latter retracted from the stylus.

7. An electric writing instrument comprising a barrel provided with astylus, means to heat the stylus, and a protector adapted to enclose andexpose the stylus, said barrel having a peripheral recess, saidprotector having an inward rib to engage said recess and having aNlongitudinal slit to permit the protector to be pressed inwardly toengage the rib with said recess.

8. An electric writing instrument comprising a barrel provided with a stvlus, means to heat the stylus, and a protector adapted to enclose andexpose the stylus. said protector having an inward lug. a stop upon thebarrel to engage said lug, and a spring 'lac liti

between the barrel and the protector c0- operative with said stop andthe protector to push the latter to conceal the stylus.

9. A writing instrument comprising a barrel having a tip provided with aborehaving a shoulder, a core in said bore having a stop againstsaidshoulder and having a stylus projecting through and from the tip, saidstylus having a stop at the outer end of the tip, a resistance conductorupon said core, 10 and line Wires in said barrel connected to saidconductor.

Signed at New York city, in the county of New York, and State of NewYork, this 23rd day of November, A. D. 1920.

CHARLES R. POST.

